This invention relates to apparatus for use on mobile machines with laterally extending devices and more specifically to mobile agricultural machines that have wing frame tool bars arranged in pivotally connected sections wherein one or more of the sections can be pivoted upward away from the ground to an elevated transport position.
Various mobile machines, especially mobile agricultural machines, include earth working implements arranged on laterally extending tool bars or wing frames. To accommodate transportation of such a machine along a highway, means are provided for pivotally swinging or folding one or more of the wing frames upwardly from a lowered ground-engaging operating position to a raised, inactive transport position.
Various conventional or non-conventional actuators may be employed to raise the wing frames. Once the wing frames are raised to the inactive transport position, mechanical or hydraulic locking systems are engaged to prevent the inadvertent lowering of the wing frames. For example, wing frames are typically raised with hydraulic actuators. In such a situation hydraulic fluid leakage in the valves, seals, lines, fittings or other places have been known to permit the weight of the wing frames, or other imposed forces, to cause the wing frames to be lowered in the absence of locking systems.
Mechanical wing frame locking systems typically require that the operator raise the wing frame by operating the controls on the machine, dismount the machine and walk to the wing frame, insert a locking pin to secure each wing frame to a portion of the main frame, and then mount the machine again.
In addition to the disadvantages inherent in this labor intensive process, it is possible for the operator to forget or purposefully decide not to carry out the wing frame locking process altogether to save time. Further, even if the wing frames are properly locked in the raised positions, it is possible for the operator to forget to remove the locking pins before operating the actuators to lower the wing frames. This can cause damage to the machinery.
Attempts to overcome the disadvantages of mechanical locking pin systems for maintaining wing frames in the raised transport positions have involved the use of automatically operated lock-up systems employing hydraulic actuators. Such lock-up systems are expensive, requiring the use of additional hydraulic piston-cylinder actuators, valves, and hoses.
Other attempts to overcome the disadvantages of mechanical locking pin systems for maintaining wing frames in the raised transport positions and for automatically decoupling wing frames when the frames are to be lowered have involved modifying several of the system components including, for instance, adding features to the wing frames, adding complex linkage components between the cylinders and the wing frames, etc. While these solutions work in theory, these solutions often increase overall costs as modifications to several components and additional components are required.
In addition, in at least some cases, these solutions require relatively complex linkages that require additional maintenance and are prone to malfunction. For instance, in at least some of these cases mechanical interaction between relatively small components is required to transfer forces along specific trajectories where the relative movements of components can be hampered or even blocked by field debris that becomes lodged between adjacent components.